68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Mac 128k screen image compressed on one side.
Posted by: Tinkerer of things on 2020-05-13 10:57:03
So here is where I'm at with this, When I got it it did nothing I replaced it's flyback transformer and a BU406D transistor. Last night I replace all the electrolytic capacitors hoping that would fix it, but no luck. Anyone have any ideals?  I should also say tryed tweaking the dials on the back side of its analog board.

Thanks

IMG_20200513_132551.jpg
Posted by: IlikeTech on 2020-05-25 19:09:09
Was the transistor you replaced the HOT?
Posted by: techknight on 2020-05-26 06:11:15
If the BUD transistor is the HOT, thing you have to make sure of is that you replaced it with the exact same transistor. Substitutions generally dont work in circuits like these as its a tuned circuit. 

Besides that, the yoke could be bad. Inspect it. 
Posted by: Tinkerer of things on 2020-06-01 01:15:15
If the BUD transistor is the HOT, thing you have to make sure of is that you replaced it with the exact same transistor. Substitutions generally dont work in circuits like these as its a tuned circuit. 

Besides that, the yoke could be bad. Inspect it. 
Thank you, I will have a look and swap out the BUD again. 
Posted by: Tinkerer of things on 2020-06-01 01:16:06
Was the transistor you replaced the HOT?
Yes, its heatsink was actually discoloured.
Posted by: techknight on 2020-06-01 11:01:35
ouch. yea theres some issues going on there. the transistor is being overloaded potentially. Also, check the damper diode and make sure it isnt leaky or shorted. 
1